The enzymatic renin reaction in vivo is inhibited in mice during inter-male aggressiveness.

In aggressive male mice with very high plasma renin concentrations the plasma angiotensin II (ANG II) and III (ANG III) concentrations were measured in single mice in order to study whether this renin was active in vivo. The angiotensins were purified and identified by ion-exchange chromatography and High Pressure Liquid Chromatography (HPLC) and quantitated by a specific and sensitive radioimmunoassay. Plasma ANG II and ANG III values were not elevated in aggressive mice compared to normals, in spite of the fact that the plasma renin concentration was increased up to 100 fold and almost equal to the plasma renin-substrate concentration. This indicates an inhibition of the enzymatic renin reaction in vivo during aggression, which is in accordance with the lack of blood pressure increase, and an unchanged pressure sensitivity to ANG II.